Effects of K on Rice Blast and Yield Under Different Nitrogen Managements in Cold Area of China

【Objective】Study on the relationship between disease-resistant ability and K-N application in rice production and to identify the effects of K application on increasing disease-resistant ability of rice.【Method】Different N management and K combinations were designed in field plot experiment. 【Result】Results showed that compared with no K addition, K application decreased rice blast spike number by 25.8%-30.2% under SSNM (site-specific nitrogen management ). Compared with farmer’s fertilization practice (FFP), disease index of rice blast under SSNM system decreased by 33.1% (P0.05) and 34.9% (P0.05) with same K rate. Yield increase from 13% to 16% was observed with application of K rates at 60 kg·ha -1 and 90 kg·ha -1 compared to FFP and no K addition. 【Conclusion】 Proper K application under SSNM can increase the resistant ability to blast, 1 000-grain weight, and plump grain rate in rice, and therefore increase rice yield.